The retraction of tissue during surgery and other medical procedures is particularly difficult where the tissue that must be retracted is deep tissue or organs where there is limited space in which to position retraction devices. One such medical procedure is the repair or replacement of heart valves. In the case of procedures involving the mitral valve or the tricuspid valve, the valve is usually accessed through an incision in the wall of the heart at the left atrium in the case of the mitral valve, or the right atrium in the case of the tricuspid valve. The tissue surrounding this incision is retracted to enable the surgeon to reach the valve, and the tissue forming the wall of the atrium must also be retracted to prevent the walls of the atrium from closing in and obstructing the valve. Retraction devices are frequently large and unwieldy when working in close quarters such as during open heart surgery.